Statistical analysis
Data were statistically analyzed using SPSS 23.0 and MedCalc 16.2. Data
were expressed as mean ± SD or as d number (percentage). Difference of
variance was calculated by a variance ratio test (F-test). To compare
continuous variables, we used the independent sample t test. For
categorical variables, we applied the Chi-square test.
The Inter- and intra-observer reproducibility of LUSS was assessed by
using Bland-Altman plot, with a coefficient of variation, Pearson’s
correlation, and intra-class correlation coefficient (ICC). The
coefficient of variation was defined as the standard deviation of
differences between two readings in the percentage of the mean. P values
< 0.05 were considered statistically significant.